private static void DrawPolyLineImpl(Graphics g, Color color, Point[] points)
{
if (points.Length < 1)
{
return;
}
uint nativeColor = (uint)(color.R + (color.G << 8) + (color.B << 16));
IntPtr hdc = IntPtr.Zero;
IntPtr pen = IntPtr.Zero;
IntPtr oldObject = IntPtr.Zero;
try
{
hdc = g.GetHdc();
pen = SafeNativeMethods.CreatePen(NativeConstants.PS_SOLID, 1, nativeColor);
if (pen == IntPtr.Zero)
{
NativeMethods.ThrowOnWin32Error("CreatePen returned NULL");
}
oldObject = SafeNativeMethods.SelectObject(hdc, pen);
NativeStructs.POINT pt;
bool bResult = SafeNativeMethods.MoveToEx(hdc, points[0].X, points[0].Y, out pt);
if (!bResult)
{
NativeMethods.ThrowOnWin32Error("MoveToEx returned false");
}
for (int i = 1; i < points.Length; ++i)
{
bResult = SafeNativeMethods.LineTo(hdc, points[i].X, points[i].Y);
if (!bResult)
{
NativeMethods.ThrowOnWin32Error("LineTo returned false");
}
}
}
finally
{
if (oldObject != IntPtr.Zero)
{
SafeNativeMethods.SelectObject(hdc, oldObject);
oldObject = IntPtr.Zero;
}
if (pen != IntPtr.Zero)
{
SafeNativeMethods.DeleteObject(pen);
pen = IntPtr.Zero;
}
if (hdc != IntPtr.Zero)
{
g.ReleaseHdc(hdc);
hdc = IntPtr.Zero;
}
}
GC.KeepAlive(g);
}
